A purification device and purification method for hexachlorodisilane

Abstract

The application discloses a purification device and method for hexachloroethyldisilane, which comprises electrode groups, is provided with a plurality of groups, and is used for removing metal impurities by redox reaction occurring on the positive and negative electrodes; the electrolytic impurity removal tank is of a closed structure, an inside of the electrolytic impurity removal tank is used for mounting the electrode groups, and the electrode groups are sequentially arranged along the flow direction of raw materials and are arranged in the electrolytic impurity removal tank; the side wall of the electrolytic impurity removal tank is provided with a liquid inlet, a liquid outlet, a protective gas interface and an exhaust port; a circulating pipeline is connected with the circulating liquid inlet and the circulating liquid outlet of the electrolytic impurity removal tank; and a circulating pump is arranged on the circulating pipeline and is used for providing driving force for the circulating flow of the hexachloroethyldisilane raw material. The scheme adopts the electrolysis mode, metal cations are reduced and deposited on the negative electrode, and the removal of metal ions is more comprehensive.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hexachlorodisilane purification, and particularly relates to a hexachlorodisilane purification device and a hexachlorodisilane purification method. BACKGROUND

[0002] Compared with traditional dichlorodihydrogen silicon and silane gas deposition method for preparing a silicon film, hexachlorodisilane gas deposition method has low deposition temperature, low deposition pressure, high deposition efficiency, and better insulation, corrosion resistance and compatibility of the obtained silicon film. It is widely used in the preparation of thin film intermediate medium layer, polycrystalline silicon interconnection wire surrounding layer and gate transistor spacing layer, and is a key silicon-based semiconductor raw material for high-end chip, wafer manufacturing, memory and logic chip manufacturing.

[0003] At present, hexachlorodisilane raw materials are mainly derived from the tail gas condensate of a polycrystalline silicon system reduction furnace. The components are complex, and the content of various metal impurities is high, especially Al, Fe, Ti, V and Cr, which is several to several hundred ppb, and it is difficult to remove uniformly and efficiently. The yield of the existing process product is low, and the production cost is high.

[0004] In the related art, the main shortcomings of hexachlorodisilane purification are as follows: first, the process route using the rectification method needs multiple rectification towers, the process is complex, the one-time investment is large, the metal impurity removal effect is general, and the material loss is large; second, the process route using the extraction method has a long standing time, and organic substances can be mutually soluble, so it is difficult to effectively separate metal impurities by extraction; third, the process route using the method of adding an ether compound and then distilling only has a removal effect on titanium, and other metal impurities are not significantly reduced; fourth, the content of metal impurities in hexachlorodisilane raw materials is high, and the process route using sorbitol, chelate resin and other adsorbents to remove metal impurities needs to consume a large amount of adsorbents, the replacement frequency of the adsorbents is high, and the cost is high. SUMMARY

[0005] The present application aims to at least partially solve one of the problems in the related art.

[0006] To this end, one aspect of the present application provides a hexachlorodisilane purification device. The electrolytic impurity removal tank is improved to have a closed structure, a protective gas source is arranged on the electrolytic impurity removal tank to replace and protect the inside of the electrolytic impurity removal tank, a graphite rod electrode is arranged in the electrolytic impurity removal tank to avoid introducing other impurities, a circulating pipeline is arranged at the inlet and outlet of the electrolytic impurity removal tank, a circulating pump is arranged on the circulating pipeline to provide circulating power for the material in the electrolytic impurity removal tank, and thus the electrolysis efficiency can be further improved.

[0007] The embodiment of the other aspect of the application provides a purification method of hexachloroethydisilane, which has good metal impurity removal effect and strong pertinence; the method introduces the hexachloroethydisilane to be treated into an electrolytic impurity removal tank, removes metal cations by electrolysis, and deposits the metal cations at the negative electrode, thereby removing all metal ions, and removing high-valence heavy metal impurities with strong electron receiving ability more preferably.

[0008] According to the embodiment of the first aspect of the application, a purification device of hexachloroethydisilane is provided, which comprises electrode groups arranged in several groups, and is used for removing metal impurities by oxidation and reduction reactions occurring at the positive and negative electrodes; the electrolytic impurity removal tank is of a closed structure, and the inside of the tank is used for mounting the electrode groups, and the electrode groups are arranged in the electrolytic impurity removal tank in sequence along the flow direction of the raw material; the side wall of the electrolytic impurity removal tank has a liquid inlet, a liquid outlet, a protective gas interface, and an exhaust port, wherein the liquid inlet is used for introducing the hexachloroethydisilane to be treated into the electrolytic impurity removal tank, the protective gas interface is used for introducing inert gas into the electrolytic impurity removal tank and replacing and protecting the inside of the electrolytic impurity removal tank, the exhaust port is used for discharging the generated gas outside the electrolytic impurity removal tank through the exhaust port, and the liquid outlet is used for discharging and collecting the product after electrolysis is completed through the liquid outlet; a circulation pipeline is connected to the circulation liquid inlet and the circulation liquid outlet of the electrolytic impurity removal tank, and the circulation liquid inlet and the circulation liquid outlet are arranged on the side wall of the electrode group on the feeding side and the discharging side, respectively, so as to realize the circulation of the material in the electrolytic impurity removal tank through the circulation pipeline and the circulation liquid inlet after the material is discharged from the circulation liquid outlet; and a circulation pump is arranged on the circulation pipeline, and is used for providing driving force for the circulation of the hexachloroethydisilane.

[0009] According to the purification device of the application, electrolytic impurity removal is adopted, the electrolytic impurity removal tank has simple structure, low power consumption, low electrode replacement cost, long service life, and is convenient to maintain and repair; the circulation liquid inlet and the circulation liquid outlet are arranged on the inlet and outlet sides of the electrolytic impurity removal tank, respectively, and the material in the electrolytic impurity removal tank is driven to circulate by the circulation pipeline and the circulation pump, so that the material is continuously circulated for electrolytic impurity removal, multiple reactions, increased reaction probability, and good impurity removal effect.

[0010] As a preferred solution, the exhaust port is connected to an alkali washing unit, and is used for alkali washing treatment of the generated hydrogen chloride and chlorine.

[0011] The generated small amount of gas is treated by the alkali washing unit, which can avoid overpressure in the electrolytic impurity removal tank, and can avoid pollution of the generated harmful gas to the environment after being discharged after alkali washing.

[0012] As a preferred solution, the electrode group is provided with 2-6 groups.

[0013] As a preferred solution, the inner wall of the electrolytic impurity removal tank is provided with a PTFE or PFA lining layer, which can avoid the introduction of impurities.

[0014] As a preferred solution, the electrode group includes a positive electrode and a negative electrode, and both the positive electrode and the negative electrode adopt graphite rods. The electrode material is graphite, which has good conductivity and stable properties and does not introduce other impurities.

[0015] As a preferred solution, the number of graphite rods in each electrode group is 2 pairs to 8 pairs.

[0016] According to the second aspect of the embodiment of the present application, a purification method of hexachlorodisilane is provided, and the specific steps are as follows:

[0017] In step one, before feeding, the electrolytic impurity removal tank is replaced by high-purity inert gas through the protection gas interface to avoid the entry of air and moisture, and the pressure in the electrolytic impurity removal tank is maintained at 10-100 kPa, and the internal temperature is controlled at 10-50℃.

[0018] In step two, the hexachlorodisilane to be treated with high metal impurity content is added through the liquid inlet of the electrolytic impurity removal tank, and the volume of the added hexachlorodisilane is 85%-95% of the volume of the electrolytic impurity removal tank.

[0019] In step three, the electrode group starts to pass direct current, and the metal impurities are removed by the oxidation-reduction reaction occurring on the positive and negative electrodes of the electrode group, and the direct current voltage of the graphite rod of the electrode group is controlled at 5-48V.

[0020] In step four, the circulation of hexachlorodisilane is carried out by starting the circulating pump, and the circulation time is 4-8h.

[0021] In step five, a small amount of HCl and Cl2 is generated by oxidation on the positive electrode of the electrode group, and when the pressure of the electrolytic impurity removal tank is higher than the set pressure, it is discharged from the exhaust port and absorbed by the alkali washing unit.

[0022] In step six, after the circulation time of the electrolytic impurity removal tank reaches 4-8h, the product is collected through the liquid outlet of the electrode impurity removal tank and detected.

[0023] According to the purification method of the present application, a method for comprehensively and efficiently removing metal impurities in hexachlorodisilane is provided. By cooperating with the above-mentioned specific purification device, the process indicators are strictly controlled, and the electrolytic method is adopted. The metal cations are reduced and deposited on the negative electrode, which has a removal effect on all metal ions, and the removal effect on high-valence state and heavy metal impurities with strong electron receiving ability is better, and the removal of metal ions is more comprehensive. In the purification process, except for a small amount of tail gas, the material loss is small, and the yield of hexachlorodisilane is high.

[0024] In some embodiments, in step one, the pressure in the electrolytic impurity removal tank is 10-100 kPa, and the internal temperature is controlled at 10-50°C, preferably, the pressure in the electrolytic impurity removal tank is 30-60 kPa, and the internal temperature is controlled at 20-40°C.

[0025] In some embodiments, in step three, the graphite rod of the electrode group is controlled at a direct current voltage of 5-48 V, preferably 10-24 V.

[0026] In some embodiments, in step four, the circulating pump circulates the hexachloroethydisilane material at a volume ratio of 0.5:1-2:1 per hour to the volume of the electrolytic impurity removal tank. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0028] Figure 1 Figure 1 is a structural diagram of the purification device of the present application;

[0029] Figure 2 Figure 2 is a material circulation principle schematic diagram of the purification device of the present application;

[0030] In the figure, 1 is an electrode group, 2 is an electrolytic impurity removal tank, 3 is a liquid inlet, 4 is a liquid outlet, 5 is a protective gas interface, 6 is an exhaust port, 7 is a circulating pipeline, 8 is a circulating pump, and 9 is an alkali washing unit. DETAILED DESCRIPTION

[0031] The present application will be described in detail below through exemplary embodiments. However, it should be understood that the elements, structures, and features in one embodiment can be beneficially combined into other embodiments without further description.

[0032] It should be noted that, unless otherwise defined, the technical terms or scientific terms used herein should be understood as the usual meaning understood by those skilled in the art. The "one", "a" or "the" and similar words used in the patent application description and claims of the present application do not represent quantity limitation, but indicate the presence of at least one. The "including" or "containing" and similar words indicate that the elements or objects before "including" or "containing" cover the elements or objects listed after "including" or "containing" and their equivalents, but do not exclude other elements or objects with the same function.

[0033] As shown in the figure, in one typical embodiment of the present application, a purification device for hexachloroethane is provided, which comprises an electrode group 1, an electrolytic impurity removal tank 2, a circulating pipeline 7, a circulating pump 8 and an alkali washing unit 9, wherein the electrode group 1 is provided with a plurality of groups, each of which comprises an anode and a cathode, and is used for removing metal impurities by redox reaction occurring on the anode and the cathode thereof; the electrolytic impurity removal tank 2 is of a closed structure, and a plurality of electrode groups 1 are arranged in the electrolytic impurity removal tank 2 in sequence along the flow direction of the raw material; the two ends of the circulating pipeline 7 are connected to the side wall of the circulating inlet side and the side wall of the circulating outlet side of the electrolytic impurity removal tank 2, and when the material in the electrolytic impurity removal tank 2 is discharged from the circulating liquid outlet side, it will return to the other end of the circulating liquid inlet side of the electrolytic impurity removal tank 2 through the circulating pipeline 7 and the circulating liquid inlet; the circulating pump 8 is arranged on the circulating pipeline 7, and the circulating pump 8 is a diaphragm pump or a gear pump. Thus, driving force is provided for the circulating flow of the hexachloroethane raw material. According to the present scheme, the circulating pipeline 7 is arranged on the side wall of the circulating inlet side and the side wall of the circulating outlet side of the electrode group 1 of the electrolytic impurity removal tank 2, so that the circulating pump 8 is started to circulate, which can effectively improve the probability of the reduction deposition of the metal impurities on the cathode and improve the impurity removal efficiency.

[0034] In one embodiment of the present application, the volume of the electrolytic impurity removal tank 2 is 50L-200L, and the material is 304 or 316L stainless steel, preferably 316L, and a PTFE or PFA lining layer is arranged in the electrolytic impurity removal tank 2, so that it has good stability and corrosion resistance, and can avoid the introduction of external impurities. The working pressure in the electrolytic impurity removal tank 2 is 10kPa-100kPa, preferably 30kPa-60kPa; and the control temperature is 10℃-50℃, preferably 20℃-40℃.

[0035] In the present application, the side wall of the electrolytic impurity removal tank 2 has a liquid inlet 3 and a liquid outlet 4, wherein the purpose of arranging the liquid inlet 3 is to introduce the hexachloroethane raw material to be treated into the electrolytic impurity removal tank 2, and the liquid outlet 4 is used to discharge and collect the product for detection after electrolysis, and can also be used for displacement and pressure relief.

[0036] In one embodiment of the present application, the electrolytic impurity removal tank 2 is also provided with a protective gas interface 5 and an exhaust port 6. The purpose of arranging the protective gas interface 5 is to introduce inert gas into the electrolytic impurity removal tank 2 and to displace and protect the inside of the electrolytic impurity removal tank 2; and the exhaust port 6 is used to discharge the generated gas from the electrolysis to the outside of the electrolytic impurity removal tank 2 through the top exhaust port 6. In the electrolysis process, the anode will oxidize to generate a small amount of HCl and Cl2, and when the internal pressure of the electrolytic impurity removal tank 2 is higher than the set pressure, it will be discharged from the top exhaust port 6 and absorbed by the alkali washing unit 9.

[0037] In the application, the electrode group 1 in the single electrolytic impurity removal tank 2 is provided with 2-6 groups, preferably 4-6 groups; each group of electrode group 1 includes a positive electrode and a negative electrode, wherein the positive electrode and the negative electrode are both made of graphite, and the number of graphite rods in each group of electrode group is 2-8 pairs, preferably 4-8 pairs. The electrode material is made of graphite, which has good conductivity and stable properties and does not introduce other impurities.

[0038] Another typical embodiment of the application also provides a method for purifying hexachlorodisilane, and the specific steps are as follows:

[0039] In step one, before feeding, the electrolytic impurity removal tank 2 is replaced by high-purity inert gas through the protection gas interface 5. The static replacement is to fill high-purity nitrogen from the top protection gas interface 5, the pressure is 0.2-0.3 MPaG, and the tank is statically placed for 10-30 minutes. The pressure is released from the bottom liquid outlet 4, and the pressure is lowered to 10-50 kPaG. This process is repeated for 3-5 times. When the gas dew point in the electrolytic impurity removal tank 2 is less than or equal to -50 DEG C, and the oxygen content is less than or equal to 10 ppm, the replacement is qualified. Incomplete replacement can cause water and oxygen pollution to hexachlorodisilane. During the entire electrolytic impurity removal process, the working pressure in the electrolytic impurity removal tank 2 is maintained at 10-100 kPa, preferably 30-60 kPa; and the internal temperature is controlled at 10-50 DEG C, preferably 20-40 DEG C.

[0040] In this scheme, the high-purity inert gas can be nitrogen, preferably high-purity nitrogen, with a purity of 5N, a water content of less than or equal to 10 ppb, and an oxygen content of less than or equal to 10 ppb. The replacement of nitrogen and the protection of inert gas by nitrogen at the end can avoid the entry of external air and water, and avoid the pollution of the internal electrolytic impurity removal tank 2.

[0041] In step two, the hexachlorodisilane to be treated with high metal impurity content is added through the liquid inlet of the electrolytic impurity removal tank 2. The volume of the added hexachlorodisilane is 85-95% of the volume of the electrolytic impurity removal tank 2.

[0042] In step three, the electrode group 1 starts to pass direct current, and the oxidation-reduction reaction occurs on the positive electrode and the negative electrode to remove the metal impurities. The direct current voltage of the graphite rod of the electrode group 1 is controlled at 5-48 V, preferably 10-24 V.

[0043] In this scheme, the graphite electrode starts to pass direct current, and the oxidation-reduction reaction occurs on the positive electrode and the negative electrode to remove the metal impurities. The metal cations are reduced and deposited on the negative electrode by electrolysis, which has a removal effect on all metal ions, and has a better removal effect on high-valence heavy metal impurities with strong electron receiving ability, and has a more comprehensive removal effect on metal ions.

[0044] Step four, through the opening of circulating pump 8, the circulation of hexachloroethane silane, circulation time 4h~8h; circulating pump 8 is diaphragm pump or gear pump, circulation flow is 10L / h~200L / h, preferably 50L / h~100L / h; the volume of hexachloroethane silane material circulated per hour: electrolytic impurity removal tank 2 volume is 0.5:1~2:1.

[0045] The scheme, through the opening of circulating pump 8, the probability of reducing deposition of metal impurities on the negative electrode is improved, and the impurity removal efficiency is improved, and the circulation time is 4h~8h.

[0046] Step five, a small amount of HCl and Cl2 is generated by oxidation on the positive electrode of the electrode group 1, and when the pressure of the electrolytic impurity removal tank 2 is higher than the set pressure, the exhaust port 6 is discharged, and is absorbed by the alkali washing unit 9;

[0047] For example, the pressure in the electrolytic impurity removal tank 2 is controlled at 40kPa~50kPa, when the pressure is higher than 50kPa, the exhaust port 6 is opened to exhaust, and when the pressure is lower than 40kPa, the exhaust port 6 is closed to maintain pressure; during electrolysis, a small amount of HCl and Cl2 is generated by oxidation on the positive electrode, and when the pressure is higher than the set pressure, the exhaust port 6 at the top is discharged, and is absorbed by the alkali washing.

[0048] Step six, after circulating 4h~8h, the product is collected through the liquid outlet 4 of the electrode impurity removal tank 2 and is detected.

[0049] The present application provides a kind of purification method and device of hexachloroethane silane, use polysilicon system by-product as raw material, metal impurity content high material is pressurized after circulating pump 8, continuously circulates through electrolytic impurity removal tank 2, and redox reaction occurs on its graphite electrode surface, metal cation obtains electron at negative electrode, and is reduced into metal element, and is removed on the electrode surface;Anion is oxidized to produce HCl and Cl2 in positive electrode, and is discharged through the exhaust port 6 at the top of electrolytic impurity removal tank 2. After circulating electrolysis, the metal impurity content in hexachloroethane silane is significantly reduced, the metal impurity content can be reduced to below 20ppb, the product quality is greatly improved, the production link loss is small, and the production cost is significantly reduced.

[0050] The following is described with reference to specific embodiments:

[0051] Example 1

[0052] Step one, electrolytic impurity removal tank 2 before feeding, by the protection gas interface 5 into high purity inert gas to electrolytic impurity removal tank 2 is replaced, and keep the pressure of electrolytic impurity removal tank 2 40kPa~50kPa, control internal temperature 25℃, avoid air and moisture into; Electrolytic impurity removal tank pressure control 40kPa~50kPa, pressure is higher than 50kPa, through the exhaust port 6 automatically open to exhaust, the pressure is lower than 40kPa, exhaust port 6 is automatically closed; High purity inert gas is nitrogen, purity ≥5N, moisture ≤10ppb, oxygen ≤10ppb, by nitrogen replacement qualified;

[0053] Step two, through the liquid inlet 3 of electrolytic impurity removal tank 2 to add the six chloroethylsilane with high content of metal impurities; The volume of the added six chloroethylsilane is 90% of the volume of the electrolytic impurity removal tank 2; The material of electrolytic impurity removal tank 2 is 316L, the volume is 100L, the inner surface is lined with PTFE; The volume is 90L;

[0054] Step three, electrode group 1 starts to pass through the oxidation and reduction reaction on the positive and negative electrode, the metal impurities are removed, the positive and negative electrode material is graphite, each electrolytic impurity removal tank 2 has 4 groups of positive and negative electrodes 4, and each group of electrodes has 4 pairs of graphite rods; The electrode direct current voltage is controlled to be 24V;

[0055] Step four, the circulation of six chloroethylsilane is carried out by opening the circulating pump 8, the circulating pump 8 is a diaphragm metering pump, the circulating flow is 100L / h, the circulating time is 6h, the sampling and detection are carried out through the liquid outlet 4, and the metal impurities are detected by ICP-MS.

[0056] Step five, a small amount of HCl and Cl2 is generated by oxidation on the positive electrode of the electrode group 1, when the pressure of the electrolytic impurity removal tank 2 is higher than 50kPa, the set pressure is discharged from the exhaust port 6, and is absorbed by the alkali washing unit 9;

[0057] Step six, after 6h of circulation, the product is collected through the liquid outlet 4 of the electrode impurity removal tank 2, and the sampling and detection are carried out through the liquid outlet 4, and the metal impurities are detected by ICP-MS.

[0058] Example 1 (before and after electrolytic impurity removal)

[0059]

[0060] As can be seen from table 1, the method of the application has obvious purification effect on the six chloroethylsilane raw material with high impurity content, after electrolytic treatment, the impurities are obviously decreased, and the content of Al impurity with the highest content is lower than 20ppb.

[0061] Table 2 example 1-3 and comparative example 1 (circulation time comparison)

[0062]

[0063] Compared with Example 1, sample 1 in Table 2 is completely the same as the conditions of Example 1, the cycle time is 6h in total, and other conditions of Example 2, 3 and Comparative Example 1 are the same as those of Example 1, and the only difference is that the cycle time of sample 2 (Example 2) is 4h, the cycle time of sample 3 (Example 3) is 8h, and the cycle time of sample 4 (Comparative Example) is 2h.

[0064] As can be seen from Table 2, with the increase of cycle time, the removal efficiency of metal impurities in Examples 1-3 gradually increases, the cycle time of Comparative Example 1 is relatively short, and the efficiency decreases obviously, but too long cycle time will cause the production efficiency to decrease, and according to the quality requirements of the product, it is appropriate to select the appropriate cycle electrolysis time.

[0065] Table 3 Examples 1, 4-6 (cycle flow comparison)

[0066]

[0067] Compared with Example 1, sample 1 in Table 3 is completely the same as the conditions of Example 1, and the cycle flow thereof is 100L / h.

[0068] Examples 4, 5 and 6 are the same as Example 1 in other conditions, and the only difference is that the cycle flow of sample 2 (Example 4) is 10L / h, the cycle flow of sample 3 (Example 5) is 200L / h, and the cycle flow of sample 4 (Example 6) is 400L / h, and other conditions are the same.

[0069] As can be seen from Table 3, the cycle flow of sample 2 is too small, the cycle number per unit time is reduced, the probability of reduction of metal cations in electrolysis is reduced, and the impurity removal effect is reduced; but the cycle flow of sample 4 is too large, which will cause the material flow rate to be too fast, the impact on the electrode to increase, and the deposited impurities to fall off, so the cycle flow should be controlled in a suitable range, and the solution cycle volume per hour: electrolysis impurity removal tank volume = 0.5:1~2:1 is appropriate.

[0070] Table 4 Examples 1, 7, 8 and Comparative Example 2 (electrolysis voltage comparison)

[0071]

[0072] Compared with Example 1, sample 1 in Table 4 is completely the same as the conditions of Example 1, and the electrolysis voltage thereof is 24V, and compared with Example 1, other conditions of Examples 7, 8 and Comparative Example 2 are the same, and the only difference is that the electrolysis voltage of sample 2 (Example 7) is 5V, the electrolysis voltage of sample 3 (Example 8) is 48V, and the electrolysis voltage of sample 4 (Comparative Example 2) is 2V, and other conditions are the same.

[0073] As can be seen from Table 4, the electrode voltage of Comparative Example 2 is low, which can cause the speed of redox reaction at the electrode to be slow, and the impurity removal effect to be obviously decreased; after the voltage of Example 8 is increased, the impurity removal effect of the electrolysis impurity removal tank is increased, but too high voltage can cause the safety risk to be increased and the production cost to be increased, and 10V-24V is preferred.

[0074] The present application removes the metal impurities in hexachloroethyldisilane through the electrolysis impurity removal tank, and the metal impurities in hexachloroethyldisilane can be efficiently removed by controlling suitable circulation time, selecting suitable circulation flow according to the volume of the electrolysis impurity removal tank 2, and selecting suitable electrode voltage, and the removal effect is more obvious for the metal impurities such as Al, Ti, Cr, Fe and Cu with high content. Compared with the existing purification methods such as rectification, adsorption, extraction and ionization chlorination, the present application does not introduce other impurity components, and has comprehensive metal impurity removal, high removal rate, simple process, convenient maintenance and low cost.

[0075] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with the preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content without departing from the technical solution of the present application, and any simple modification, equivalent change and modification of the above embodiment according to the technical essence of the present application still belong to the scope of the technical solution of the present application.

Claims

1. A purification apparatus for hexachlorodisilane, characterized by: Comprising The electrode group is provided with several groups; for removing metal impurities by the oxidation-reduction reaction occurring on the positive and negative electrodes thereof; The electrolytic impurity removal tank is of a closed structure, the inside of which is used for installing the electrode group, and several electrode groups are arranged in sequence along the flow direction of the raw material in the electrolytic impurity removal tank; the side wall of the electrolytic impurity removal tank is provided with a liquid inlet, a liquid outlet, a protective gas interface, and an exhaust port, wherein the liquid inlet is used for feeding the six chloroethylsilane to be treated into the electrolytic impurity removal tank, the protective gas interface is used for feeding inert gas into the electrolytic impurity removal tank and replacing and protecting the inside of the electrolytic impurity removal tank; the exhaust port is used for discharging the electrolytic generated gas outside the electrolytic impurity removal tank through the exhaust port; and the liquid outlet is used for discharging and collecting the product after the electrolysis is completed through the liquid outlet; The circulation pipeline is connected with the circulation liquid inlet and the circulation liquid outlet of the electrolytic impurity removal tank respectively, and the circulation liquid inlet and the circulation liquid outlet are arranged on the side wall of the electrode group feeding side and the electrode group discharging side respectively, so as to realize the circulation of the material in the electrolytic impurity removal tank from the circulation liquid outlet side to the circulation liquid inlet side of the other end of the electrolytic impurity removal tank through the circulation pipeline and the circulation liquid inlet. The circulation pump is arranged on the circulation pipeline and is used for providing driving force for the circulation flow of the six chloroethylsilane raw material.

2. A device for purifying hexachlorodisilane according to claim 1, characterized in that: The exhaust port is connected with the alkali washing unit and is used for alkali washing treatment of the hydrogen chloride and chlorine generated in the electrolysis.

3. A device for purifying hexachlorodisilane according to claim 1, characterized in that: The electrode group is provided with 2-6 groups.

4. A device for purifying hexachlorodisilane according to claim 1, characterized in that: The inner wall of the electrolytic impurity removal tank is provided with a PTFE or PFA lining layer.

5. A device for purifying hexachlorodisilane according to claim 3, characterized in that: The electrode group comprises positive electrodes and negative electrodes, and the positive electrodes and the negative electrodes are both graphite rods.

6. A purification apparatus for hexachlorodisilane according to claim 5, characterized in that: The number of graphite rods in each electrode group is 2 pairs to 8 pairs.

7. A method for purifying hexachlorodisilane, characterized by: The specific steps are as follows: Step one: Before feeding, the electrolytic impurity removal tank is replaced by high-purity inert gas through the protective gas interface to avoid air and moisture from entering, and the pressure in the electrolytic impurity removal tank is maintained at 10 kPa to 100 kPa, and the internal temperature is controlled at 10℃ to 50℃; Step two: The six chloroethylsilane to be treated with high metal impurity content is added through the liquid inlet of the electrolytic impurity removal tank; the volume of the added six chloroethylsilane is 85% to 95% of the volume of the electrolytic impurity removal tank; Step three: The electrode group starts to pass direct current, and the metal impurities are removed by the oxidation-reduction reaction occurring on the positive and negative electrodes of the electrode group; the direct current voltage of the graphite rod of the electrode group is controlled at 5V to 48V; Step four: The circulation of the six chloroethylsilane is carried out by starting the circulation pump, and the circulation time is 4h to 8h; Step five: A small amount of HCl and Cl2 is generated by oxidation on the positive electrode of the electrode group, and when the pressure of the electrolytic impurity removal tank is higher than the set pressure, it is discharged from the exhaust port and absorbed by the alkali washing unit; Step six: After the circulation time of the electrolytic impurity removal tank reaches 4h to 8h, the product is collected through the liquid outlet of the electrode impurity removal tank and detected.

8. The method of purifying hexachlorodisilane according to claim 7, wherein: In step one, the pressure in the electrolytic impurity removal tank is 30kPa to 60kPa, and the internal temperature is controlled at 20℃ to 40℃.

9. The method of purifying hexachlorodisilane according to claim 7, wherein: In step three, the direct current voltage of the graphite rod of the electrode group is controlled at 10V to 24V.

10. The method of purifying hexachlorodisilane according to claim 7, wherein: In step four, the circulation pump circulates the six chloroethylsilane material volume per hour: electrolytic impurity removal tank volume is 0.5:1 to 2:1.

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